The present invention relates generally to drive systems for lawn mowers, and particularly to steering, brake, and clutch assemblies for mowing equipment. More particularly, the present invention relates to a steering clutch brake assembly for use on a walk-behind mower or other grass-cutting device.
Commercial quality walk-behind mowers have typically included a drive motor which is connected to ground-engaging wheels on both sides of the mower by a drive belt linkage. To apply motive force to the wheels, each such linkage would include a tensioning idler pulley. To brake one or more wheels, an actuator, such as a hand lever, would be provided to move the idler pulley out of tension with the drive belt and to move a band brake into engagement with the wheel. Braking one wheel was, for example, used to steer the mower, while braking wheels on both sides of the mower was effective in bringing the mower to a stop.
These prior belt linkages have proven unsatisfactory in certain circumstances. Connecting the drive shaft to the wheel, the idler pulley to the band brake, and the hand lever to the idler pulley required a cumbersome arrangement whose efficiency deteriorated relatively quickly in the field and required a significant amount of maintenance work. In addition, when a single idler pulley was used with each wheel, such prior mowers tended to free wheel off hills and could not be driven in reverse. A double idler pulley arrangement has been used to help solve those concerns, but at the expense of even more linkages and more maintenance work.
Also, in order to maintain an acceptably low level of grip force needed to actuate the hand lever, idler pulley springs have been employed which are too light to maintain optimum tension on the drive belt. As a result, prior mowers have tended to slip when climbing hills or pulling a grass catcher or riding sulky. Further, prior band brakes typically braked the wheel in only one direction and tended to wear out relatively quickly because they are open to the environment and mounted directly to the wheel. To accommodate these band brakes, specially formed and expensive wheel assemblies have been required.
Various prior mower drive systems have been proposed which do not rely on belt linkages. However, for various reasons these alternatives have not been commercially practical. Hydraulic drive systems may function well, but are prohibitively expensive. Prior clutch drive systems have typically lacked an integral brake as well as a final drive, all components remaining exposed to the environment and a belt drive linkage connecting the clutch to the wheel. Other prior clutch drive systems have been relatively bulky, requiring special construction of the mower deck to accommodate it, and not being readily adaptable to existing mower decks.
Accordingly, it is an object of the present invention to provide an improved drive system for mowers. Another object of this invention is to provide an inexpensive and reliable mower drive system that incorporates steering and braking capabilities. Yet another object is to provide a mower drive system that can be easily maintained and repaired and readily fitted to existing mower deck structures.
There is a need for a mower drive assembly that is able to provide greater driving torque to the wheels in forward and reverse directions of drive, with minimal necessary user actuation force. A compact steering, brake, and mower drive assembly whose components are shielded from the work environment and a drive assembly having a greater useful life and utilizable with standard wheel assemblies would also be an improvement over conventional mower drive assemblies.
According to the present invention, a self-contained steering, clutch, and brake assembly is provided for use in a lawn mower. This steering, clutch, and brake assembly includes a housing for connection to a rotating drive shaft. A brake hub is mounted to the housing and a clutch drum is movable between connection with the drive hub or the brake hub. A drive hub is mounted on an extension of the drive shaft. The connections between the clutch drum and the drive or brake hubs are made through floating coaxial multi-disk clamping assemblies which serve to increase engagement surface area within the minimal confines of the housing.
The clutch drum is always connected to a standard-size wheel axle through a compound reduction chain drive which is also enclosed by the housing. The clutch drum is biased normally into engagement with the drive hub. A cam actuator is provided to disengage the clutch drum and drive hub and to move the clutch drum into engagement with the brake hub. The housing is adapted to be bolted directly to the mower deck without special deck reconfiguration.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of a preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.